Treatment of acid tar.



UNITED STATES PATENT a ms WILHELM 0. TH. TIENEN, OF EOTTERDAM,NETHERLANDS, ASSIGNOR TO DE BATAAFSOHE PETROLEUM MAATSCHAPPIJ, OF THEHAGUE, NETHERLANDS, A.

CORPORATION OF THE NETHERLANDS.

TREATMENT OF ACID TAB.

No Drawing.

Specification of Letters Patent.

Application filed October 21, 1910. Serial No. 588,303.

Patented Aug. 15, 1911'.

To all whom it may concern:

Be it known that I, \VILHELM O'r'ro THAARUP VAN TIENEN, a subject of thethe like, nearly the whole of the acid used for the treatment beingrecovered at the same time.

In the various methods for purifying if mineral oils and distillatestherefrom, con-' centrated sulfuric acid is mixed with the crude oil andthis mixture continuously stirred and, under some conditions, heated. Ifnow the mass is left to itself, two layers are formed of which the upperlayer consists of purified oil (illuminating oil) and 'the other of amixture of sulfonic acids formed by the action of the sulfuric acid onaromatic and unsaturated hydrocarbons, which mixture constitutes the socalled acid tar. In the reaction of aromatic and unsaturatedhydrocarbons with sulfuric acid to form sulfonic acids, water isliberated. Since this reaction is reversible, it has been attempted, byintroducing steam, to re-convert' the sulfonic acids into heavyhydrocarbons and sulfuric acid. This has not led to an economicalresult; since the yield of recovered hydrocarbons is too small. It istrue that the steam carries along with it the greater part of thehydrocarbons, but the consumption of steam is too costly. Moreover thesulfuric acid liberated is impure and cannot be concentrated withoutfundamental regeneration. I have discovered that the reversal of thesaid reaction yields commercial products if instead of steam, a certainproportion of water is added to the sulfonic acids and the mixture isheated under pressure. In this manner the sulfuric acid is obtainedsufiiciently'diluted and clean, and

can be very well-concentrated without previous regeneration, while theheavy hydro carbons also separate in a pure state According to theinvention a certain pro- -hour to two hours.

7 portion of water, previously determined in relation to the kind ofsulfoni'c acids to be treated, the excess of sulfuric acid mixed withthe acid tar and the degree of dilution thereof, is added to the acidtar. This mixture of water and 'acidtaris then heated in.

duration of the heating depends on the kind of acid-tar, and ranges froma quarter of an In practicing the invention, therefore,a

predetermined quantity of wateris added ,to

the sulfonic acids and then the mixture'is heated in a closed vessel toabout 140165 C and at a pressure of about seven atmospheres. Thehydrocarbons and; sulfuric acid are only regenerated from the mixtureif, the other conditions (temperature ,and

pressure) being favorable, the sulfuric acid present or formed, dilutedby the quantityof water added, has a certain concentration. The acid taris therefore heated withv a quantity of water which brings the sulfuricacid present and formed, to the desired degree of concentration. Thesulfonic acids are then split up, if the temperature and pressureconditions. are right, into the original aromatic hydrocarbons andsulfuric acid. Three layers are formed, of which the uppermost consists.of pure hydrocarbons, which can be used directly, after washing withwater, as motor oils and for other purposes, the lowest layer consistsof pure d1- luted sulfuric acid capable of direct concentration, whichcan be used again for purifying mineral oils or their distillates, whilebetween these two layers there is formed a very thin layer, whichcontains small residues of acid and resinified tar. Owing to thisStratification the various products can easily be separated. a I

The proportion of 'water to be added to the acid tar as mentioned above,depends on the kind of hydrocarbons present in the tar as sulfonicacids, because these hydrocarbons determine each byits composition thepro ortion of sulfuric acld combined 1n the "sul onic acid and also theproportion of free (reckoned as acid of 1,692 specific gravity equal to'59? Baum) are ascertained and the quantity of water necessa forsuflicient dilution is then calculate The excess of free acid remainingfrom the acid of 66 Baum specific gravity originally used has beendiluted to 59?,Baum specific gravity by the water liberated during thesulfonation. For the reaction which is to occur in the pressure vessel,the quantity of water added mustbe such as to dilute this excess ofacid'and that liberated by the water from the sulfonicadids, to 52 Baumspecific gravity. An acid of the specific gravity last named cannotre-sulfonate the oils. The quantity of water is therefore so reckonedthat the, acid present after the action has a specific gravity of 1,565specific gravity equal to 52 Baum only to insure that the acid shall nothave a sulfonating action. It is not advisable to add a largerproportion ofwater, since this would dilute the acid unnecessarily andincrease the cost of subsequent concentration.

The following example illustrates the inve11tion:--An acid tar whichcontains for each 100 parts by wei ht 43 parts by weight of combinedacid 0 66 Baum speclfic gravity and 14 parts by weight free acid of 59Baum specific gravity, must be heated for two hours at 165 C. and 7atmospheres pressure with 233 parts by weight of water.

The liquid separates into two layers, of which the-one consists of theregenerated oils and the other'of sulfuric acid of about, at the most,52 .Baum specific gravity. These twolayers can be separated in anyknownmanner and the acid concentrated to 66 Baum specific gravity. Inthis man- 'the free acid existing in the acid tar, to a specific gravityof not more than 52 Baum and heating themixture at a pressure of about 7atmospheres and at a temperature of about 140165 C. y

In testimony whereof I have hereunto set my hand in presence of twosubscribing wit- :Witnesses:

- ANTONIO ELBERTS DoYER,

.THOMAS U. VERHAVE.

